Modular expansion joint

ABSTRACT

Modular expansion joints made from aluminum extrusions providing longitudinal frames and longitudinal rails. The rails have an Ibeam-like structure with upwardly opening channels respectively receiving and interlocking therein deformable beads on the lower surface of an elastomer tread with hollow, V-sections deforming downwardly as the joint width becomes narrow. The elastomer tread completely covers and spans the joint. The longitudinal rails are supported by solid load-bearing beams having a greater width than depth, and coil springs are interposed between contiguous rails.

United States Patent [191 Rina et al.

1 1 MODULAR EXPANSION JOINT [75] Inventors: Michael C. Rizza, WalnutCreek.

Calif; Belmont D. Brown, North Baltimore. Ohio [73} Assignee: The D. S.Brown Company, North Baltimore, Ohio 221 Filed: May 7,1973

21 Appl.No.:358.059

Related US. Application Data [63] Continuation-impart of Scr. No.121.957. Feb. 8.

1971, Pat. No. 3.732.021.

[52] US. Cl. 404/69 [51] Int. Cl. E01c 11/02 [58] Field of Search404/47, 48, 60, 68, 69,

[56] References Cited UNITED STATES PATENTS 1.977.496 10/1934 Snyder404/47 X 2,043,571 6/1936 Bargrcen... 404/60 2.255.599 9/1941 Olmsted...404/60 2.321.873 6/1943 404/47 X 2.494.869 1/1950 Godwin 404/60 Apr. 29,1975 3.113.493 12/1963 Rinker 14/16 X 3.323.426 6/1967 Hahn 404/483.363.383 1/1968 La Barge 404/68 X 3.418.898 12/1968 Cimini 404/483.606.826 9/1971 Bowman 404/69 8 3.720.474 3/1973 Stog 14/16 X PrimaryExaminerNile C. Byers. Jr. Almrney, Agent. or FirmJohnston. Keil,Thompson 8L Shurtleff [57] ABSTRACT Modular expansion joints made fromaluminum extrusions providing longitudinal frames and longitudinalrails. The rails have an l-beam-like structure with upwardly openingchannels respectively receiving and interlocking therein deformablebeads on the lower surface of an elastomer tread with hollow. V-sectionsdeforming downwardly as the joint width becomes narrow. The elastomertread completely covers and spans the joint. The longitudinal rails aresupported by solid load-bearing beams having a greater width than depth.and coil springs are interposed between contiguous rails.

12 Claims. 4 Drawing Figures whim 1 MODULAR EXPANSION JOINT RELATEDAPPLICATION This application is a continuation-in-part of ourapplication Ser. No. 121.957. filed Mar. 8. I971 now US. Pat. No.3.732.021.

INTRODUCTION The subject invention concerns improvements in expansionjoint structures useful in the spanning of relatively wide joints inpavement surfaces. particularly joints in pavement decks of bridges. Thelatter joints have a relatively wide range of movement. i.e.. openingand closing. during expansion and contraction of sections of a bridgedeck as the environmental temperature changes.

Expansion joints for bridges heretofore have involved heavy assembliesor subassemblies brought to the bridge site and mounted in the bridgejoints by cranes or the like. One well known type of bridge expansionjoint comprises a pair of heavy duty plates fixedly attached to oppositesides of the joint. The plates have projecting, interfitting fingerswhich span the joint and can move relative to each other if the jointopens or closes. Joints of this type cannot be effectively sealedagainst leakage of water from rain or melted ice or snow. The latter twoin particular carry with them corrosive salts which. over a period oftime. damage the superstructure of the bridge. its piers. and/orabutments.

Bridge designers and engineers have been giving more attention in recentyears to use of bridge joints which are sealed against leakage of waterand/or solids through the joint onto the underlying structure of thebridge. A relatively recent design for a sealed bridge joint embodieslongitudinal. spaced rails resting on joint-spanning beams. Laterallycompressible elastomer seals are compressed between the rails slightlybelow the upper surface thereof. The upper surfaces of the rails liesubstantially in the plane ofthe bridge deck. The tires of automobilescrossing the joint run across these upper surfaces of the rails whilethe elastomer seals are recessed enough to avoid contact with theautomobile tires.

These known expansion joints are manufactured and preassembled at anoff-site facility. compressed to a width allowing them to be inserted inthe joint. hauled to the bridge site and laid in the joint with heavyduty cranes. Once installed. they are difficult to repair. Repair orreplacement of a component usually involves closing the entire bridge orseveral lanes thereof to traffic in order that heavy duty equipment maybe brought to the joint site to raise the expansion joint. repair it.and replace it back in the joint.

THE INVENTION HEREIN This invention provides improvements in expansionjoints having ranges of movement which are lesser than those attainablein the modular bridge joint of the aforesaid copending application. thelatter having loadbearing beams which are segmentally interconnected toallow the beams to lengthen or shorten the movement of the joint. Theimprovements of the subject invention reside in modular expansion jointshaving a shallower overall depth attained through, inter alia. the useof load-bearing beams of solid material, e. g.. aluminum or steel, laidin the joint in a manner where the width exceeds the depth of therespective beams. Further improvements of the invention reside in theconfiguration of the seal and tread which spans and covers the entirejoint. particularly in the provision of upper and lower V-shaped wallswith a hollow space therebetween in the sections of the tread extendingbetween respective longitudinal rails. Other improvements reside in themanner of mounting the outermost rails in the longitudinal frames onopposite sides of the joints.

The metal components of the joint include longitudinal frames mounted instepped edges of a concrete pavement deck. such as the concrete pavementdeck of a bridge. or in other concrete structures such as pavementsections adjoining or contiguous to bridges. The longitudinal railsextend longitudinally of the joint in substantially equally spacedrelationship. These rails may be made in short sections and splicedtogether in end-to-end relationship in the manner shown in the aforesaidapplication.

The frames. rails and load-bearing beams preferably are fabricated asaluminum alloy extrusions. Each extrusion is relatively light in weightso that the joint can be assembled manually at the joint site withoutusing heavy duty equipment. The rails are of relatively short lengths.e.g.. 12 feet. This feature allows the joint to be constructed orrepaired on a one lane at a time basis. while keeping other lanes opento traffic flow during maintenance. The frame sections provided at eachside of the joint also preferably are made in short sections and mayhave a gasket between abutting ends to seal the abutting ends againstseepage of water at these points.

The joints of the invention are constructed in standard unit lengths andwill span joints of medium width. e.g.. joints having a maximum openingof 8-l2 inches. The coil springs between the rails maintainsubstantially equal spacing therebetween regardless of joint width. Theends of the coil springs respectively are composed of horizontal legswhich seat in a groove provided in the lower portion of the l-beamlikerails and a diagonal leg. the tip of which seats in an opposite grooveof said rails.

The load-bearing beams or bars extend through aligned openings providedin the respective rails and span the entire joint between respectiveouter rails. The longitudinal frames at each side of the joint areprovided with a recess segment into which the ends of the load-bearingbeams or bars can project when the joint closes arid the ends of theload-bearing beams or bars begin to extend into the longitudinal framemembers of the joint.

The frames at the edges of the joint are extrusions which may be placedat the time of the initial deck paving. Secure mounting of the frames inthe deck pavement is accomplished by anchor bolts embedded in theconcrete and tied to reinforcing steel in the deck pavement.

The elastomer seal and tread provides a continuous seal from curb tocurb without joints subject to leakage. The seal has longitudinal beadswhich snap into channels on the upper edges of the rails thus making theseal easy to install'or replace. The seal covers all of the metalstructure of the joint and is the only part which could be damaged bysnowplows. The interlocking of the seal with the rails assures positivesealing in that the seal must move as the joint components move duringthermal expansion or contraction of the joint.

THE DRAWINGS A preferred embodiment of the invention is illustrated inthe drawings. wherein:

FIG. 1 is a vertical section of an expansion joint with the concretesegments of the joint shown in fragment;

FIG. 2 is a section view taken on section plane 22 of FIG. 1 without theelastomer tread;

FIG. 3 is a fragmentary. bottom plan view of abutting sections of an endframe member of the joint; and

FIG. 4 is a fragmentary detail in side elevation of the bracket and boltconnection for the abutting sections.

Referring to the drawings. the modular expansion joint spans a space 14between adjacent sections 11 and 12 of a concrete bridge deck. Thesections 11 and 12 each have a step 13 on which the longitudinal endframes 14 and 15 are seated and held in place by conventional J-bolts orother type of anchor bolts 16 or like holding devices The anchor boltshave treaded shanks which tread into nuts 17 seated in longitudinalslots 18 and 19 which extend the length of the frame sections 14 and 15.The nuts 17 are placed in the slots 18 at any desired longitudinalspacing. The J-bolts may then be treaded into the nuts until the boltand nut bind in the respective slots 18 and 19. This mounting of thenuts in the slots has proven very advantageous in installation ormounting of the frame sections on the bridge structure. The nuts may bepositioned anywhere in the slots and thus can be located on thejob siteto allow the anchor blots to interfit with or avoid interfering contactwith other components of the bridge deck or its understructure.

The longitudinal end frames preferably are aluminum extrusions having anupper. rearwardly projecting lip 20 forming an undercut 21 beneath whichconcrete can flow. The frames 14 and 15 preferably also have a smallforward lip 22 adapted to overlie the respective ends of the eiastomertread 23. The lip 22 helps provide a seal against intrusion of sand andother incompressibles between the seal and the frame and also aids inholding the respective ends of the elastorner tread in position in therespective end frames 14 and 15.

The lower portion of the end frames 14 and 15 includes a rearwardlydirected wall 24 joined to the bottom wall 25 by a connecting wall 26which flares in an upward direction to accommodate the longitudinal slot18. A chamber 27 is provided between the upper and lower walls 24 and25. which chambers will receive and accommodate the ends of theload-bearing beams or bars 28 when the joint 10 closes to its minimum ornear minimum width.

The lower wall 25 of the end frame includes an enlarged segment toaccommodate the longitudinal slot 19 and further form a seat 30 for thelower wall 31 of the respective end rails 32. which are mounted on therespective end frames.

The intermediary rails 33 are of the same cross section as the outermostrails 32. Their lower walls 39 with upturned ends 34 providelongitudinal rigidity for the rails and forming grooves 48, laterdescribed. Their upper ends have wall segments 35 like the bottom wall39 and further include U-channels 36 with inwardly directed lips 37 forreceiving deformable. dovetailed tongues 38.

The elastomer tread 23 may be made in sections which fit side-by-sideacross the width of the joint. Each section includes an end wall 40having a sawtoothed or serrated upper side edge 41. The latter interlockand form a seal against intrusion of water between abutting faces of thetread sections. The contacting faces of the end walls 40 are positivelysealed against water leakage therebetween by tight-fit and compressionof the portions of tongues 38 which seat between the neck formed by theopposed. inwardly directed lips 37. The side-byside. lower portions ofthe abutting edges together form as a composite dovetailed tongues 38a.

The remainder of the elastomer tread may include one or more solidelastorner segments 42 between the end walls 40, each solid segmentbeing located above a U-channel 36 with a dovetailed tongue 38 dependingtherefrom. The intermediary portions of the tread sections between therespective rails are composed of a shallow, V-shaped upper wall 43 and ashallow, V- shaped lower wall 44 with a hollow space 45 therebetween. Asthe joint closes and the elastomer tread is pushed inwardly from itsrespective ends. the shallow. V-shaped walls 43 and 44 assume a deeper.V- configuration. Only the upper wall 43 is essential to make the sealwaterproof. However. the lower wall 44 gives symmetric stability to thetread sections and serves as a second sealing surface. should the upperwall 43 become punctured or torn.

Adjacent one side of each load-bearing beam or bar 28 there is provideda coil spring 46 between each rail. The respective rails have opposedupper and lower grooves 47 and 48 on each side thereof. The lower groove48 on each rail receives a horizontal leg 49 at each end of the coilspring while the upper groove 47 receives the end 50 ofa diagonal leg 51extending from one end of the respective legs 49. These diagonal legsprovide a useful function in holding the coil springs 46 in place undervibrations imparted to the joint by traffic passing thereover. Springswithout such diagonal legs and mounted only by the horizontal legs 49have been found. on occasion. to work loose as a result of thevibrations imparted on the joint by traffic moving thereover.

The outer rails 31 and 32 are held in position on the longitudinal endframe members 14 and 15 by a T-bar 52, the cross leg of which is seatedin opposed grooves 53 and 54 of the frame. The other leg 55 is connectedby bolt 56 to a T-bar 57 having edge portions seated in the opposedgrooves 58 and 59 of the outermost rails. One or both of the parallellegs of the T-bars may have a slot allowing for adjustable positioningof the respective bars in the end frames and the outermost rails.

The load-bearing beams or bars 28 have attached at opposite ends thereofby bolts 60 or other suitable means. a plate 61 whose length is greaterthan the width of the load-bearing beams or bars 28. The respectiveplates 62 serve as stops to prevent either end ofthe beams or bars 28from passing through the outermost rails 31 and 32.

The half tongues 38b of the elastorner tread are seated in end frames byproviding an inverted L-leg 62 spaced from and directed toward the wallportion 63 of the end frames. The horizontal lip of the half tongues 38blies beneath the horizontal leg of the inverted L-leg 62 continuallyalong the longitudinal dimension of the joint. The vertical leg of thehalf tongues 38b are compressed between the end of the L-leg and theopposing face of wall portion 63 to make a constant. water-tight seal.This interlocking. coupled with the lips 22 overlying the upper side ofthe outer edge of the tread section. hold the tread section firmly inplace in the respective end frames. Further. the upper portion of thewall 63 may be provided with serrations 64 to match and receive theserrated side portion 4] of the outer most wall of the seal sectionforming the tread. This further aids in preventing seepage of moistureand incompressibles between the contacting faces of the side walls 40 ofthe outermost seal and the face of the wall 63 of the frame.

Preferably the rectangular opening 65 in the interme diary rails 33 andoutermost rails 32 are lined with a wear-resistant bushing 66. e.g., agasket-like lining of Adiprene.

In preferred forms of the invention. the rails 33 and 32 and the endframes l4 and are aluminum extrusions approximately l2 feet in length.which length corresponds to one lane of a dual line or multilane highwayor bridge. The abutting ends of the rails 32 and 33 are spliced togetherby elongated plates of the type shown in our application aforesaid.which splicing plates are seated in the opposed grooves 47 and 48 oneach side of the respective rails at the point or points of splicing. Byusing lengths corresponding substantially to lane widths of the highwaysor bridges. it is possible to repair or inspect or conduct periodicmaintenance of the joint by closing off only one late at any given timein the performance of the aforesaid functions.

The invention thus provides a modular joint structure utilizing a pairof elongated, longitudinal frames mounted firmly in concrete or otherpaving material on steps at the respective edges of the joint. Aplurality of elongated, longitudinal rails span the joint in parallel.spaced relationship to each other. These rails respec tively haverectangular openings therein disposed at longitudinal intervals alongthe rails. The openings are aligned in a plurality of transverse rowsthrough which joint-spanning. load-bearing beams of rectangular crosssection extend through at least some. and usually all. of the rows ofrectangular openings. The respective rails. excepting the two outermostrails. rest individually and independently slidable on the rectangularload-bearing beams.

To maintain substantially equal spacing between the respective rails.the modular joint structure utilizes a plurality of coil springs mountedbetween respective rails and preferably in an arrangement providing aplurality of longitudinally spaced. transverse rows close to but spacedfrom one side of the load-bearing beam.

The modular joint is sealed over its entire width and length byproviding an upper. elastomer tread having solid elastomer segmentsabove and supported on the upper portions of the respective rails.preferably by deformable beads or tongues interlocked in channelformingmembers on the upper surface ofthe rails. The intermediary portions ofthe treads between the rails preferably comprise upper and lower.vertically spaced, shallow V-shaped walls with a hollow spacetherebetween. As the joint closes. these upper and lower walls deforminto a deeper V-configuration.

The tread preferably is composed of a series of sideby-side elastomersegments made from low crystallization neoprene formulations. Theabutting edges of the treads with the sides of the longitudinal endframes and with another side of an adjacent tread segment for awater-tight seal. ln the illustrated embodiment. the tread sectionscomprise three sideby-side sections 67,

Lit

68 and 69 of identical cross section and a section 70 which is one-halfthe width of the tread sections 67-69. If desired. the tread sectionsmay comprise three or more integrally formed sections. each of whichcorresponds in cross section to section 70 in the same manner assections 67-69 comprise the equivalent of two sections 70. By suchdimensions and geometry of the tread sections. they can be used to spanjoints of vary ing width dimension through appropriate selection of thetread section widths needed to span the particular joint between thelongitudinal end frames 14 and IS.

The sections of the longitudinal end frames 14 and 15 preferably arealso sealed at their junctures by an elastomer gasket. Referring toFIGS. 3 and 4, the end portions ofthe longitudinal slots or grooves 19of abutting frame sections 14a and 14b have placed therein a nut 71. AnL-bracket 72 is fixedly attached to the underside of the bottom wall 25of each frame section. the horizontal leg 73 of which is held by a bolt74. The shank of the bolt projects through a hole or slot (not shown) inthe leg 73 and is threaded into the nut 71 to hold L-bracket 72 fixedlyon the bottom wall.

The vertical leg 75 of each L-bracket has a boltreceiving hole throughwhich the shank 76 of bolt 77 extends. An elastomer gasket 78 conformingto the cross section of the frame 14 is placed between the framesections 14a and 14b and is compressed therebetween by drawing uptightly the bolt 77 and its nut 79.

Similar bracket and bolt means may be mounted in the longitudinal slotsor grooves 18 to draw the abutting frame sections together and give amore uniform compression of the gasket 78.

lt is through that the invention and its numerous attendant advantageswill be fully understood from the foregoing description, and it isobvious that numerous changes may be made in the form. construction andarrangement of the several parts without departing from the spirit orscope of the invention. or sacrificing any of its attendant advantages.the form herein disclosed being a preferred embodiment for the purposeof illustrating the invention.

The invention is hereby claimed as follows:

I. A shallow modular joint structure useful for spanning jointscomprising a pair of elongated longitudinal frames adapted to be mountedat the respective edges of the joint. a plurality of elongated.longitudinal rails spanning the joint in parallel. spaced relationshipto each other. said rails respectively having openings therein atlongitudinally spaced intervals. said openings further being aligned ina plurality of transverse rows. said openings being of rectangular crosssection and having a horizontal width greater than the vertical depth.and a plurality of joint-spanning load-bearing beams of rectangularcross section with a horizontal width greater than the respectivevertical depth of each beam and extending through at least some of saidrows of rectangular openings with said rails resting slidably thereon.

2. A joint structure as claimed in claim 1. said rails having mountedtherebetween a plurality ofcoil springs arranged in a plurality oflongitudinally spaced. transverse rows.

3. A joint structure useful for spanning joints com prising a pair ofelongated longitudinal frames adapted to be mounted at the respectiveedges of the joint. a plurality of elongated. longitudinal railsspanning the joint in parallel. spaced relationship to each other. saidrails respectively having openings therein at longitudinally spacedintervals. said openings further being aligned in a plurality oftransverse rows. said openings being of rectangular cross section andhaving a width greater than the depth. and a plurality ofjoint-spanningload-bearing beams of rectangular cross section with a width greaterthan the respective depth of each beam and extending through at leastsome of said rows of rectangular openings with said rails having mountedtherebetween a plurality of coil springs arranged in a plurality oflongitudinally spaced. transverse rows. said springs balancing thespacing between respective rails at the joint structure widens ornarrows. said spring members each having horizontal legs at oppositeends thereof seated in leg'receiving groove means in respective railsand diagonal end portions extending from said legs with the tip portionsof the diagonal end portions seated in opposed groove means inrespective rails.

4. A joint structure as claimed in claim I. said longi tudinal frameshaving formed therein longitudinally extending cavities into which theends of the jointspanning. load-bearing beams can extend as the jointapproaches its narrowest spacing.

5. A modular joint structure useful for spanning joints comprising apair of elongated, longitudinal frames adapted to be mounted onrespective sides of the joint. a plurality of elongated. longitudinalrails spanning the joint in parallel relationship to each other.plurality of joint-spanning. load-bearing beams extending transverselyacross the joint and supporting the respective rails. an elastomer treadcomposed of one or more tread sections. means supporting said tread onthe upper portion of each rail with a solid elastomer strip portion ofthe tread above and supported by each rail. and said solid portionsbeing connected by at least one shallow V-shaped wall connectingrespective upper corner portions of said solid portions of said tread.

6. A joint structure as claimed in claim 5. said tread also having alower. shallow V-shaped wall below and spaced from said first-mentionedwall and defining a hollow space between said walls and solid portions.

7. A joint structure as claimed in claim wherein said tread sectionshave dformable members depending from said solid portions andinterlocking in channelforming means extending along the upper sides ofrespective rails.

8. A joint structure as claimed in claim 5. said longitudinal frameshaving longitudinal groove means for receiving an interlocking memberdepending from the end wall of said tread mounted on said frame. andsaid frame further having an elongated lip overlying the upper corner ofsaid tread.

9. A joint structure as claimed in claim 5. said tread comprising aplurality of side-by-side sections extending longitudinally of the jointand interlocking serrations formed in the contiguous. abutting sidewalls of respective tread sections.

10. A modular joint structure useful for spanning joints comprising apair of elongated, longitudinal frames adapted to be mounted onrespective sides of the joint. a plurality of elongated. longitudinalrails spanning the joint in parallel relationship to each other. aplurality of joint-spanning. load-bearing beams extending transverselyacross the joint and supporting the respective rails. said frames havingone or more downwardly facing. longitudinal slots. nuts slidablypositionable at any desired point in said slot or slots. and an chorbolts having threaded ends threaded into said nuts until the nuts andbolts bind in the slot or slots. the shanks of said bolts projectingfrom the frame for M choring in pavement poured adjacent and beneathsaid frames.

ll. A modular joint structure useful for spanning joints comprising apair of elongated. longitudinal frames adapted to be mounted onrespective sides of the joint. a plurality of elongated. longitudinalrails spanning the joint in parallel relationship to each other. aplurality of joint-spanning. load-bearing beams extending transverselyacross the joint and supporting the rails. said frames being composed ofaligned sections. a gasket between abutting ends of said section. saidsections each having a downwardly facing longitudinal slot portion nearrespective abutting ends. a nut slidably adjustably seated in each slotportion. a bracket mounted on the inside of each section adjacentrespective abutting ends by a bolt threaded into a respective nut ineach slot portion and bolts connecting respective pairs of brackets ofrespective abutting ends for drawing said ends together and compressingtherebetween said gasket.

12. A modular joint structure as claimed in claim 11. said bolts havingthreaded ends threaded into said nuts until the nuts and bolts bind insaid respective slots.

* l t i

1. A shallow modular joint structure useful for spanning jointscomprising a pair of elongated longitudinal frames adapted to be mountedat the respective edges of the joint, a plurality of elongated,longitudinal rails spanning the joint in parallel, spaced relationshipto each other, said rails respectively having openings therein atlongitudinally spaced intervals, said openings further being aligned ina plurality of transverse rows, said openings being of rectangular crosssection and having a horizontal width greater than the vertical depth,and a plurality of joint-spanning load-bearing beams of rectangularcross section with a horizontal width greater than the respectivevertical depth of each beam and extending through at least some of saidrows of rectangular openings with said rails resting slidably thereon.2. A joint structure as claimed in claim 1, said rails having mountedtherebetween a plurality of coil springs arranged in a plurality oflongitudinally spaced, transverse rows.
 3. A joint structure useful forspanning joints comprising a pair of elongated longitudinal framesadapted to be mounted at the respective edges of the joint, a pluralityof elongated, longitudinal rails spanning the joint in parallel, spacedrelationship to each other, said rails respectively having openingstherein at longitudinally spaced intervals, said openings further beingaligned in a plurality of transverse rows, said openings being ofrectangular cross section and having a width greater than the depth, anda plurality of joint-spanning load-bearing beams of rectangular crosssection with a width greater than the respective depth of each beam andextending through at least some of said rows of rectangular openingswith said rails having mounted therebetween a plurality of coil springsarranged in a plurality of longitudinally spaced, transverse rows, saidsprings balancing the spacing between respective rails at the jointstructure widens or narrows, said spring members each having horizontallegs at opposite ends thereof seated in leg-receiving groove means inrespective rails and diagonal end portions extending from said legs withthe tip portions of the diagonal end portions seated in opposed groovemeans in respective rails.
 4. A joint structure as claimed in claim 1,said longitudinal frames having formed therein longitudinally extendingcavities into which the ends of the joint-spanning, load-bearing beamscan extend as the joint approaches its narrowest spacing.
 5. A modularjoint structure useful for spanning joints comprising a pair ofelongated, longitudinal frames adapted to be mounted on respective sidesof the joint, a plurality of elongated, longitudinal rails spanning thejoint in parallel relationship to each other, plurality ofjoint-spanning, load-bearing beams extending transversely across thejoint and supporting the respective rails, an elastomer tread composedof one or more tread sections, means supporting said tread on the upperportion of each rail with a solid elastomer strip portion of the treadabove and supported by each rail, and said solid portions beingconnected by at least one shallow V-shaped wall connecting respectiveupper corner portions of said solid portions of said tread.
 6. A joinTstructure as claimed in claim 5, said tread also having a lower, shallowV-shaped wall below and spaced from said first-mentioned wall anddefining a hollow space between said walls and solid portions.
 7. Ajoint structure as claimed in claim 5 wherein said tread sections havedformable members depending from said solid portions and interlocking inchannel-forming means extending along the upper sides of respectiverails.
 8. A joint structure as claimed in claim 5, said longitudinalframes having longitudinal groove means for receiving an interlockingmember depending from the end wall of said tread mounted on said frame,and said frame further having an elongated lip overlying the uppercorner of said tread.
 9. A joint structure as claimed in claim 5, saidtread comprising a plurality of side-by-side sections extendinglongitudinally of the joint and interlocking serrations formed in thecontiguous, abutting side walls of respective tread sections.
 10. Amodular joint structure useful for spanning joints comprising a pair ofelongated, longitudinal frames adapted to be mounted on respective sidesof the joint, a plurality of elongated, longitudinal rails spanning thejoint in parallel relationship to each other, a plurality ofjoint-spanning, load-bearing beams extending transversely across thejoint and supporting the respective rails, said frames having one ormore downwardly facing, longitudinal slots, nuts slidably positionableat any desired point in said slot or slots, and anchor bolts havingthreaded ends threaded into said nuts until the nuts and bolts bind inthe slot or slots, the shanks of said bolts projecting from the framefor anchoring in pavement poured adjacent and beneath said frames.
 11. Amodular joint structure useful for spanning joints comprising a pair ofelongated, longitudinal frames adapted to be mounted on respective sidesof the joint, a plurality of elongated, longitudinal rails spanning thejoint in parallel relationship to each other, a plurality ofjoint-spanning, load-bearing beams extending transversely across thejoint and supporting the rails, said frames being composed of alignedsections, a gasket between abutting ends of said section, said sectionseach having a downwardly facing longitudinal slot portion nearrespective abutting ends, a nut slidably adjustably seated in each slotportion, a bracket mounted on the inside of each section adjacentrespective abutting ends by a bolt threaded into a respective nut ineach slot portion and bolts connecting respective pairs of brackets ofrespective abutting ends for drawing said ends together and compressingtherebetween said gasket.
 12. A modular joint structure as claimed inclaim 11, said bolts having threaded ends threaded into said nuts untilthe nuts and bolts bind in said respective slots.